Mixing apparatus



. 1959 w. EbwARDs ETAL 2,867,386

MIXING APEARATUS 2 Sheets-Sheet l Filed April 19, 1956 Jan. 6, 1959 G. w. EDWARDS ETAL 2,867,386

MIXING APPARATUS 7 Filed April 19, 1956 2 Sheets-Sheet 2 United rates a ainst MIXING APPARATUS George Wilfred Edwards and Roger Joseph Sevin,

' Paris, France.

Application April 19, 1956, Serial N0. 579,224 Claims priority, application France April 20, 1955 4 Claims. (Cl. 241-46) This invention relates to mixing, dispersing or emulsifying apparatus.

When using mixing apparatus, comprising a mixing head which includes a rotor element rotatable within a cage or, stator element, in order to carry out mixing simultaneously with grinding, it follows that if the grinding effect is satisfactory then the flow through the apparatus willbecome inadequate and thus the turbulence in the vat or container in which the mixing head is disposed will be reduced and dead zones will be formed within such vat or container.

It is an object of the present invention to provide means whereby the disadvantage indicated above may be obviated and whereby without impairing the turbulence and mixing action achieved by a mixing head, a simultaneous grinding effect may be achieved.

According to the invention, in a mixing head there is provided a rotor including a plurality of blades and adapted on operation to set up two independent parallel mixing and grinding circuits, such rotor also comprising vanes at the end portions of the blades which are adapted to cooperate with at least one stationary disc thereby to set up a shearing effect on some of the material circulated by said rotor.

In order that the said invention may be clearly understood and readily carried into effect the same will now be more fully described with reference to the accompanying drawings in which:

Figure 1 is. a part sectional side elevational view of a rotor assembly to be incorporated in a mixing head adapted for mixing substances in vats or the like and incorporating the features of the invention,

Figure 2 is a plan view of the rotor shown in Figure 1, the upper disc shown in Figure 1 being removed,

Figure 3 is a part sectional side elevational view illustrating one method of supporting a mixing head incorporating the rotor illustrated in Figure l, and

Figure 4 is a section on the line IV-IV of Figure 3.

Referring now to Figures 1 and 2, 1 denotes the hub of the rotor such hub being of rectangular form and having blades 2 fixed to each face thereof. Each blade comprises a vertical portion 3 which is fixed on the hub and extends beyond the latter. Provided at the upper and lower edges of the central portion of each blade 2 are vanes 4 and 5 which are so arranged that on rotation of the rotor liquid will be sucked in from above and below the latter. As a result, two currents of liquid will be set up, one in the direction shown by the arrows 6 and the other in the direction indicated by the arrows 7. These two currents meet one another at the central portions of the of the blades 2 and are expelled radially.

In addition to the vanes 4 and 5 two further vanes 8 and 9 are provided at each side of the outer end portion of each blade 2 such vanes 8 and 9 bieng inclined at an angle indicated by 10 relatively to a plane which is perpendicular to the axis of rotation of the rotor.

Two stationary discs 11 and 12 are arranged at each side of the rotor opposite the planes of rotation of the 2 vanes 8 and 9, the arrangement being such that when the rotor rotates, between said two discs 11 and 12, some of the product passing through the mixing head will be forced into the angle of engagement 10 and will therefore be drawnandsheared between the surfaces of the discs 11 and 12 and the edges of the vanes 8 and 9 nearest the said discs. The result is that a mixing circuit will be set up as indicated by the arrows 6 and 7 and a grinding circuit as indicated by the arrows 13 and 14.

In order to increase the shearing effect, the surfaces of the discs may include protuberances or indentations instead of being flat. These indentations may be circular or preferably of spiral form. The discs may also, in some cases, be made of a very hard abrasive material such as corundum or the like and similarly the surface of the vanes 8 and 9 may be made of a hard material such as tungsten carbide or the like.

In Figure 1, the discs 11 and 12 are plane in the sense of the planes generated by the vanes 8 and 9 when the latter rotate. However, if the surface generated by the edges of the vanes 8 and 9 were conical, the surface of the discs would also be conical.

Moreover, although in Figure 1 two discs 11 and 12 are provided so as to balance out lateral thrusts, it will be apparent that the vanes 8 or 9 and the corresponding disc may be dispensed with at one side of the rotor blades.

- Figures 3 and 4 illustrate one particular arrangement for carrying the invention into effect.

As will be seen on reference to those figures the rotor constructed in the manner shown in Figure l is mounted directly on a shaft 15 adapted to be driven by a motor. 16 denotes a plate which is carried by three rods 17 the latter being connected for example to the bearing of the shaft 15 so that the plate will remain stationary. The shaft 15 is centred and guided with respect to the plate 16 by means of a guide 18 supported by three arms 19.

Mounted on the lower face of the plate 16 is a disc corresponding to the disc 11 of Figure 1, one face of such disc being situated opposite the end vanes 8 of the blades of the rotor as described and illustrated in Figure 1. The disc 11 is secured to the plate 16 by means of a plurality of bolts or the like 20 which also serve to support a second disc corresponding to the disc 12 of Figure 1.

The mixing head above described and illustrated may be used with advantage in any case wherein pigments or pulverulent material are to be disposed in a liquid vehicle, such as in the preparation of paints, enamels, inks, or other dyestuffs.

We claim:

1. In a mixing head for mixing materials incorporating a mixing rotor into which the materials to be mixed are drawn from the top and bottom of the rotor which in turn discharges the mixed materials at its periphery, the rotor comprising a hub, a plurality of outwardly-projecting blades attached to the hub in planes parallel to the axis of rotation of the rotor, each of the blades carrying a vane projecting from each of its upper and lower edges inwardly from its outer end portion, said vanes carried by the blades being disposed so that on rotation of the rotor two independent streams of the materials to be mixed are drawn into the rotor from above and below the rotor, mixed together within the rotor and thrown outwardly along the projecting blades, the improvement comprising a stationary annular disc adjacent and lapping said outer end portions of the projecting blades, and a vane projecting from the edge of each blade adjacent to said disc in a direction opposite to the direction of rotation of the rotor and extending along and cooperating with the adjacent surface of the disc to effect a shearing Patented Jan. 6, 1959 and grinding action on at least a portion of the material throw-n outwardly by the rotor along the blade and the adjacent surface of the annular disc.

2. A mixing head as claimed in claim 1, in which the surface of the annular disc adjacent the blades of the rotor include means for effecting a grinding action between the discand the adjacent vanes carried by the blades.

3. A mixing head as claimed in claim 1, inwhich the vanes adjacent to the surface of the annular disc are inclined from the respective edges of the blades toward the adjacent surface of the annular disc.

4'. In a mixing headfor mixing materials incorporating a mixing rotor intowhich the materials to be mixed are drawn from the top and bottom of the rotorwhich in turn discharges the mixed materials at its periphery, the

rotor comprising a hub, a plurality of outwardly-projecting blades attached to the hub in planes parallelto the axis of rotation of the rotor, each of the blades carrying means for inducing independent streams of materialsto be mixed from above and below the rotor into the rotor where the materials are mixed together Withinthe rotor and thrown outwardly along the projecting blades, the

respective discs to effect a shearing and grinding action on at least a: portion of the; materialtthrowni outwardly by the rotor along the blades and the adjacent surfaces of the annular discs.

References Cited in thev file of this patent UNITED STATES PATENTS 2,384,952 Miller Sept. 18, 1945 2,390,579 Fritzberg Dec. 11, 1945 2,390,898 Rechtin etal Dec.. 11, 194-5 2,464,588 Knudsen et a1 Mar..15, 1949* 2,706,621 Laird -Q. Apr. 19', FOREIGN I 1,083,889 France Ian. 

